East india resin coating compositions



Patented Aug. 4, 1942 msr mom nnsm COATING Robert C. ams, Stami OyanamidCo ration of Maine COMPOSITIONS Swain, Riverside, and Pierrepont Adord,Conn, assignors to American mpany, New York, N. Y., a corpo- No Drawing.Application November 26, I940, Serial No. 367,219 I 4 Claims.

This invention relates to coating compositions containing Pale EastIndia resin and melamineformaldehyde resins.

Anobject of this invention is to improve the physical and chemicalproperties of coating compositions containing Pale East India resin, e.g., solvent resistance, acid resistance, water resistance, etc.

- Another object of this invention is to provide compositions containingPale East India resin and compatibleprcportions of compatiblemelamineformaldehyde resins.

These and otheri objects are attained by blend- 4 mg File East Indiaresinwith at least about 60% (total sblids'weight' basis) ,of amelamine-formaldehyd resin which has been alkylated with an alcoholcontaining' at least 4 carbon atoms and wherein the 'ii' 'olal ratio offormaldehyde to 'melamine is at least about 4:1.

The following examples in which the proportions are in parts by weightare illustration and not in limitation.

Exsmns 1 v j arts Melamine-formaldehyde resin A 90 Pale East IndiaMacassar resin -10 A composition containing these ingredients isprepared by admixing 180 parts of melamine-- I formaldehyde resin Asolution (50% resin) with 40 parts of Pale East India resin stocksolution" (containing 25% of' Pale East India Macassar resin and 75% oftoluene). Films of the composition are applied to metal objects andbaked at a temperature of about 135 C. for about one-half hour. Theproduct is a hard, transparentcoating having good fllm strength. I

v ,Exsmnn 2 Parts Melamine-formaldehyde resin B 75 Pale East IndiaMacassar resin. 25

a composition containing these ingredients is prepared by admixing 150parts of melamineformaldehyde resin "3 solution (50% resin) with 100parts of "Pale East India resin stock solution. Films of the compositionare applied to metalobjects and baked at a temperature of about 135 C.for about one-halt-houn- A clear, tough film is formed.

I Examnr: 3

- Parts Melamine-formaldehyde resin 90 given by way of parts of "PaleEast India resin stock solution.

5 Films of the composition are applied to metal objects'and baked at atemperature of about 135 C. for about one-half hour. The product formedis a very hard, clear coating. I

EXAMPLE 4 I I 4 1 1 I Part3 Melamine-formaldehyde resinfD. 75 PaleEastIndia Macassar resin 25 A composition containingthese ingredients isprepared by admixing 150 parts of melamineform-' aldehyde resin Dsolution (50% resin) with 100 parts oi' "Pale East India resin stocksolution.-

Films of the composition are applied to metal objects and baked ata-temperature oiabout 135 C. for about one-half hour. A water-white filmhaving good chemical properties is formed.

Exmru: 5 Parts Melamine-formaldehyde resin E" .90 Pale East IndiadMacassar resin 10 A composition containing these ingredients is preparedby admixing 180 parts of melamine-formparts of Pale East India resinstock solution."

Films of the composition are applied to metal objects and baked at atemperature of about 135 C. for about one-half hour. A hard, transparentfilm is'produced. Preparation of melamine-formaldehyde resin .4. v Parts'Melamine '(1 mol) 126 Formalin (4 mols) (37% formaldehyde in -40 water)a 324.4 N-butanol 440 This mixture is placed in a reflux apparatus whichis provided'with a condenser and a suitable water trap through which the,refiux condensate passes on its return to the reaction chamber and inwhich the essentially aqueous fraction of the condensate may beseparated from theessentially non-aqueous fraction and means is providedso that the former fraction may be drawn 01! if desirable. The reactionmixture is refluxed ata temperature of about 91-93 C. at atmosphericpressure for 6-12 hours The. water is removed by azeotropic distillationfrom the'reaction mix- Pale East India Macassar resin. 10 ture duringthe reflux operation beginning prefer- A composition containing theseingredients is prepared by admixing parts of melamine-*form aldehyderesin C solution (50% resin) with 40 y aldehyde resin E solution(50%resin) with'40 Melamine (1 mol) Formalin (6 mols) (37% formaldehyde inably after about 2-5 hours have elapsed and the Preparation ofmelamine-formaldehyde resin "B" Parts Melamine (1 mol) 126 Formalin (5mols) (37% formaldehyde in water) 4055 N-butano1 440 This mixture isplaced in a reflux apparatus which is provided with a condenser and asuitable water trap through which the reflux condensate passes on itsreturn to the reaction chamber and in which the essentially aqueousfrac- C and the resin solution is concentrated to about 60-70% solids byvacuum distillation. I The resulting resin .solution may be diluted toabout 50% solids with any desired solvent or diluent, 'e. g.,

xylene. Preparation of melamine-formaldehyde resin "D Parts Melamine (1mol) 128 Formalin (5 mols) (37% formaldehyde in water) 405.5 N-hexylalcohol 500 Methyl alcohol 200 This mixture .is placed in a refluxapparatus which is provided with a condenser and a suitable water trapthrough which the reflux condensate passes on its return to the reactionchamtion of the condensate may be separated from the essentiallynon-aqueous fraction and means is provided so that the former fractionmay be drawn ofi if desirable. The reaction mixture'is refluxed at atemperature of about 91-93 C. at

atmospheric pressure for 6-12 hours. The water is removed by azeotropicdistillation from the reaction mixture during the reflux operationbeginning preferablyafter about 2-5 hours'have elapsed and the water soremoved is separated from the reflux condensate in the water trap.During the distillation about 550 additional parts of butanol are addedgradually. When the reflux 'condensateis substantially anhydrous thevapor temperature will be about IOU-105 C. The pressure is loweredsumciently to reduce the vapor temperature to about 85-90" C. and theresin solution is concentrated to about 60-70% solids by vacuumdistillation. The resulting resin solu- .tion may be diluted to about50% solids with any desired solvent or diluent, e. g., xylene.Preparation of melamine-formaldehyde resin "(1 Parts water) 486.6N-butanol 440 This mixture is placed in a reflux'apparatus which isprovided with a condenser and a suitable water trap through which thereflux condensate passes on its return to the reaction chamber and inwhich the essentially aqueous fraction of the condensate may beseparated from the essentially non-aqueous fraction and means isprovided so that the former fraction may be drawn. off if desirable.

The reaction mixture is refluxed at a temperature.

of about 91-93 C. at atmospheric pressure for 6- 12 hours. The water isremoved by azeotropic distillation from the reaction mixture during thereflux operation beginning preferably after about 2-5 hours have elapsedand the water so removed" is separated from the reflux condensate in thewater trap. During the distillation about 550 additional parts ofbutanol are added gradually.

When the reflux'condensate is substantially anto reduce the vaportemperature to about 85-90 hydrous the vapor temperature will be about.100-105 C. The pressure is lowered suflicient y ber and in which theessentially aqueous fraction of the condensate may be separated from theessentially non-aqueous fraction and means is provided so that theformer fraction may be drawn off if desirable. -The reaction mixture isrefluxed at a'temperature of about -85 C. at

atmospheric pressure for 6-12 hours. The water is removed by azeotropic'distillation from the reaction mixture during the reflux operationbeginning preferably after about 2-5hours have elapsed and the .water soremoved is separated from the reflux condensate in the water trap. whenthe reflux condensate is substantially anhydrous the vaportemperature-will be about loo-105 C. The pressure is loweredsufliciently to reduce the vapor temperature to about 90 C. and theresin solution is concentrated to about 60-70% solids by vacuumdistillation. This solution is essentially a hexylated resin is hexylalcohol, all or nearly all of the methanol having been eliminated fromit during the distillation.

The resulting resin solution may be diluted to about 50% solids with anydesired solvent or diluent, e. g., xylene.

Preparation of melamine-formaldehyde resin "E PartsMelamine-formaldehyde (moial ratio 1:4)

spray-dried powder .L 200 2-ethyl hexanol 280 N-butanol 320 Methyl acidphosphate 4 The melamine-formaldehyde condensation prodnot is obtainedby refluxing melamine and formalin (37% formaldehyde in water) in themolal ratio of 1:4 at a pH of about 7-9 for about 3 hours and thenspray-drying.

The spray dried melamine-formaldehydepowder, octanol, butanol and methylacid phosphate are heated to about -105 C. in 30 minutes and refluxedabout 30 minutes. This solution is vacuum concentrated at about 50-70'C. to form a product containing about 50% solids.

Alkylated melamine-formaldehyde resins may,

be produced in accordance with the procedures outlined above, as well asin any other suitable manner. Aqueous syrups of melamine-formaldehyderesins may be first produced and then alkylated either simultaneouslywith dehydration or subsequent to dehydration. Generally thesimuitaneous condensation of melamine, formaldehyde and a suitablealcohol is used because of convenience. .In order to facilitate thealkyiation with the higher alcohols, e. 3., the amyl alcohols. hexylalcohols and the octanols, a low .boilins alcohol such as methanol orbutanoi may be mixed with the higher alcohol, thereby assisting maybeused in place of part in removing the water and causing the reactionto take place readily at somewhat lower temperatures than wouldotherwise be required. The low boiling alcohol is removed bydistillation after the-reaction is completed. Another method forproducing resins alkylated with a higher alcohol is to alkylate themelamine-formaldehyde resin with a low boiling alcohol such as methanoland subsequently replacing it with the desired higher alcohol,distilling out the low boiling alcohol. The condensation may be carriedout either with or without an acid catalyst and in some instances basiccatalysts may desirably be utilized.

The melamine-formaldehyde resins vary slightly according to minorvariations in control during their production and in some instancessmall proportions of a suitable solvent material; e. g., benzene,toluene, xylene, turpentine, petroleum hydrocarbons, ethyl ether, etc.,may be added to the original solutions of Pale East India resin andmelamine-formaldehyde resin in order to produce perfectly clearsolutions if such solutions are not originally obtained.

While formaldehyde has been used in the previous examples, it will beobvious that the various polymers of formaldehyde, e. g.,paraformaldehyde, or substances which yield formaldehyde dehyde.

As indicated by the above examples Pale East India resin has been foundto be compatible with hyde to melamine than 6:1 may be used, it isgenerally undesirable inasmuch as formaldehyde is lost during the curingin its cured conditiondoes not contain more than about 6 mols offormaldehyde to 1 mol of melamine.-

The resins may be alkylated with any of the straight chain or branchedchain alcohols containing at least 4 carbon atoms. The term "alkylatedmelamine-formaldehyde resin is intended to denote compositions which arereacted with an alcohol.-

Our products may be plasticized. with a wide variety of materials suchas the alkyl phthalates, tricresyl phosphate, various alkyd resins,particularly the fatty oil acid modified alkyd resins, etc.

Various fillers, be added to our. compositions, e. g., .lithopone, zincoxide, titanium oxide, ferric oxide, Prussian blue, toluidine red,malachite green, mica, glass fibers. ground glass, powdered silica, etc.

Curing catalysts may be incorporated in, the compositions to eflect amore rapid curing of the melamine-formaldehyde resins or to enable thepigments, dyes and lakes may.

or-all of the formalare, for instance,

- oil, etc.

. 3 resin to be cured-at lower temperatures than indicated in the aboveexamples. Suchsubstances phosphoric acid, ammonium salts of phosphoricacid, etc. 1

Other resinous compositions may be included in various coatingcompositions, e. g., urea-formaldehyde resins, phenol-formaldehyderesins, alkyd resins, ethyl cellulose, cellulose acetate,nitrocellulose, etc., as well as in vamishes, especially drying oilvarnishes, such as those from tung oil, linseed Ourmixed products showimproved chemical resistance, solvent resistance and are much lessthermoplastic than Pale East India resin compositions not containingmelamine-formaldehyde resins.

Our compositions are useful in the manufacture of paints andvamishes,-as well as in lacquers, printing inks, adhesives andmiscellaneous decorative and protective'coating compositions. Our

products are useful in coating and impregnating paper and cloth forvarious purposes. Our products are particularly suitable for theproduction of varnishes and paints having a high gloss.

The term compatible as used herein is intended to denote compositions,films of which are clear and homogeneous after baking.

Obviously many modifications and variations in the processes andcompositions described above may be made without departing from thespirit and scope of the invention as defined in the apwe claim mixturesof melaminehyde resin to so that usually the product pended claims.

We claim:

1. A coating composition containing a substantial proportion of PaleEast India resin and a melamine-formaldehyde resin which has been.

alkylated' with an alcohol containing at least 4 carbon atoms whereinthe molal ratio of formaldehyde to melamine is at least about 4:1 andwherein the weight ratio of melamine-formalde- East India resin is atleast about 2. A coating composition containing a sub-' stantialproportion of Pale East India resin and a melamine-formaldehyde resinwhich-has beenalkylated with n-butanol wherein the molal ratio offormaldehyde to melamine is at least about 4:1 and wherein the weight,ratio of melamine-formaldehyde resin to East India resin is at least3:2.

'3. A coating composition containing a substantial proportion of PaleEast India resin and a melamine-formaldehyde resin which has beenalkylated with n-hexyl alcohol wherein the molal alkylated with ratio offormaldehyde to melamine is at leastabout 4:1 and wherein the weightratio of melamine-formaldehyde resin to East India resin is at leastabout 3:2. 4. A coating composition containing a substantial proportionof Pale East India resin anda melamine-formaldehyde resin which has been2-ethyl hexanol wherein the molal ratio of formaldehyde to melamine itat least about 4:1 and wherein the weight ratio of melamine-formaldehyderesin to East India is at least about 3:2.

ROBERT c. swam PIERREPONT AnAMs.

